Space

May 31, 2013

NASA’s Swift reveals new phenomenon in a neutron star

nasa-swift
Astronomers using NASA’s Swift X-ray Telescope have observed a spinning neutron star suddenly slowing down, yielding clues they can use to understand these extremely dense objects.

A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. A neutron star can spin as fast as 43,000 times per minute and boast a magnetic field a trillion times stronger than Earth’s. Matter within a neutron star is so dense a teaspoonful would weigh about a billion tons on Earth.

This neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses.

Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar’s rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate.

“Astronomers have witnessed hundreds of events, called glitches, associated with sudden increases in the spin of neutron stars, but this sudden spin-down caught us off guard,” said Victoria Kaspi, a professor of physics at McGill University in Montreal. She leads a team that uses Swift to monitor magnetars routinely.

Astronomers dubbed the event an “anti-glitch,” said co-author Neil Gehrels, principal investigator of the Swift mission at NASA’s Goddard Space Flight Center in Greenbelt, Md. “It affected the magnetar in exactly the opposite manner of every other clearly identified glitch seen in neutron stars.”

The discovery has important implications for understanding the extreme physical conditions present within neutron stars, where matter becomes squeezed to densities several times greater than an atomic nucleus. No laboratory on Earth can duplicate these conditions. A report on the findings appears in the May 30 edition of the journal Nature.

The internal structure of neutron stars is a long-standing puzzle. Current theory maintains a neutron star has a crust made up of electrons and ions; an interior containing oddities that include a neutron superfluid, which is a bizarre state of matter without friction; and a surface that accelerates streams of high-energy particles through the star’s intense magnetic field.

The streaming particles drain energy from the crust. The crust spins down, but the fluid interior resists being slowed. The crust fractures under the strain. When this happens, a glitch occurs. There is an X-ray outburst and the star gets a speedup kick from the faster-spinning interior. Processes that lead to a sudden rotational slowdown constitute a new theoretical challenge.

On April 21, 2012, just a week before Swift observed the anti-glitch, 1E 2259+586 produced a brief, but intense X-ray burst detected by the Gamma-ray Burst Monitor aboard NASA’s Fermi Gamma-ray Space Telescope. The scientists think this 36-millisecond eruption of high-energy light likely signaled the changes that drove the magnetar’s slowdown.

“What is really remarkable about this event is the combination of the magnetar’s abrupt slowdown, the X-ray outburst, and the fact we now observe the star spinning down at a faster rate than before,” said lead author Robert Archibald, a graduate student at McGill.

Goddard manages Swift, which was launched in November 2004. The telescope is operated in collaboration with Pennsylvania State University in University Park, Penn., the Los Alamos National Laboratory in New Mexico and Orbital Sciences Corp. in Dulles, Va. International collaborators are in the United Kingdom and Italy, and the mission includes contributions from Germany and Japan.




All of this week's top headlines to your email every Friday.


 
 

 

Headlines March 4, 2015

News: Pentagon: Another BRAC will save money - Pentagon planners have a new pitch to lawmakers skeptical of a fresh round of base closings: We promise we’ll save money this time.   Business: China’s new C919 will begin test flights this year - China’s new superjet will take to the skies for the first time later this...
 
 
Air Force photograph by SrA. Jensen Stidham

World War II pilot reunited with P-47

Air Force photograph by SrA. Jensen Stidham Retired Air National Guard Chief Warrant Officer 2 Robert Hertel, laughs while under the wing of a P-47 Thunderbolt during the Heritage Flight Training and Certification Course Feb. 2...
 
 

News Briefs March 4, 2015

General: 8,500 Islamic State fighters killed in Iraq so far The U.S.-led military coalition in Iraq has killed more than 8,500 Islamic State fighters since its bombing campaign began in August, the top general overseeing the coalition said March 3. Army Gen. Lloyd Austin, the commander of U.S. Central Command, said the Islamic State, which...
 

 
Lockheed Martin photograph

Turning up the heat

Lockheed Martin photograph Lockheed Martin ATHENA laser weapon system defeats a truck target by disabling the engine, demonstrating its military effectiveness against enemy ground vehicles. Latest evolution of Lockheed Martin l...
 
 

USO Visit

Air Force photograph by Jet Fabara Actor Vince Vaughn speaks with Edwards Airmen and 412th Security Forces Squadron members at the base library before introducing an advance screening of his new movie, “Unfinished Business,” at the base theater Feb. 28.
 
 

Sikorsky S-97 RAIDERô team begins final assembly of second aircraft

Sikorsky Aircraft Corp., a subsidiary of United Technologies Corp., announced March 4 the start of final assembly of the second S-97 RAIDERô helicopter at the company’s Development Flight Center. Along with a team of industry suppliers, Sikorsky is developing two RAIDERô prototypes to demonstrate the revolutionary new capabilities in improved maneuverability and flight speed. The...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>